Regular transfusions are effective in managing strokes in paediatric sickle cell patients. However, there are associated risks, including alloimmunisation and iron overload. This study evaluated the efficacy of top-up transfusions in primary and secondary stroke prevention in a single tertiary paediatric centre in Central London. Forty-seven children with sickle cell disease who received transfusions in the last decade were included. No patient on a primary stroke prevention transfusion programme had a cerebrovascular event during the study period but 9.5% on secondary stroke prevention programme did. Twenty-one per cent of patients in this cohort converted to exchange transfusions following transfer to adult services, of which 11% had subsequent strokes. Targeted pre-transfusion haemoglobin S % was not always met; 43% of HbS% readings in a 12- month period were above the set target of 30% and 37% were above the set target of 50%. About a third of patients had evidence of severe hepatic iron overload, but no significant cardiac iron. 25% of patients became alloimmunised, but not severe enough to warrant discontinuation of the transfusion programme. Although transfusions are effective for primary stroke prevention, iron overload remains a significant burden.